Two-phase, water-based immersion-cooling apparatus with passive deionization

ABSTRACT

Cooling apparatuses, cooled electronic modules and methods of fabrication are provided for fluid immersion-cooling of an electronic component(s). The method includes, for instance: securing a housing about an electronic component to be cooled, the housing at least partially surrounding and forming a compartment about the electronic component to be cooled; disposing a fluid within the compartment, wherein the electronic component to be cooled is at least partially immersed within the fluid, and wherein the fluid comprises water; and providing a deionizing structure within the compartment, the deionizing structure comprising deionizing material, the deionizing material ensuring deionization of the fluid within the compartment, wherein the deionizing structure is configured to accommodate boiling of the fluid within the compartment.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. Ser. No. 13/187,556, entitled“Two-Phase, Water-Based Immersion-Cooling Apparatus with PassiveDeionization,” filed Jul. 21, 2011, and which is hereby incorporatedherein by reference in its entirety.

BACKGROUND

The power dissipation of integrated circuit chips, and the modulescontaining the chips, continues to increase in order to achieveincreases in processor performance. This trend poses a cooling challengeat both the module and system level. Increased airflow rates are neededto effectively cool high power modules and to limit the temperature ofthe air that is exhausted into the computer center.

In many large server applications, processors along with theirassociated electronics (e.g., memory, disk drives, power supplies, etc.)are packaged in removable node configurations stacked within a rack orframe. In other cases, the electronics may be in fixed locations withinthe rack or frame. Typically, the components are cooled by air moving inparallel airflow paths, usually front-to-back, impelled by one or moreair moving devices (e.g., fans or blowers). In some cases it may bepossible to handle increased power dissipation within a single node byproviding greater airflow, through the use of a more powerful air movingdevice or by increasing the rotational speed (i.e., RPMs) of an existingair moving device. However, this approach is becoming problematic at therack level in the context of a computer installation (i.e., datacenter).

The sensible heat load carried by the air exiting the rack is stressingthe ability of the room air-conditioning to effectively handle the load.This is especially true for large installations with “server farms” orlarge banks of computer racks close together. In such installations,liquid cooling (e.g., water cooling) is an attractive technology tomanage the higher heat fluxes. The liquid absorbs the heat dissipated bythe components/modules in an efficient manner. Typically, the heat isultimately transferred from the liquid to an outside environment,whether air or other liquid coolant.

BRIEF SUMMARY

In one aspect, a method of fabricating a cooled electronic module isprovided. The method includes: securing a housing about an electroniccomponent to be cooled, the housing at least partially surrounding andforming a compartment about the electronic component to be cooled;disposing a fluid within the compartment, wherein the electroniccomponent to be cooled is at least partially immersed within the fluid,and wherein the fluid comprises water; and providing a deionizingstructure within the compartment, the deionizing structure comprisingdeionizing material, the deionizing material ensuring deionization ofthe fluid within the compartment, wherein the deionizing structure isconfigured to accommodate boiling of the fluid within the compartment.

Additional features and advantages are realized through the techniquesof the present invention. Other embodiments and aspects of the inventionare described in detail herein and are considered a part of the claimedinvention.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

One or more aspects of the present invention are particularly pointedout and distinctly claimed as examples in the claims at the conclusionof the specification. The foregoing and other objects, features, andadvantages of the invention are apparent from the following detaileddescription taken in conjunction with the accompanying drawings inwhich:

FIG. 1. depicts one embodiment of a conventional raised floor layout ofan air-cooled data center;

FIG. 2 depicts one embodiment of a coolant distribution unitfacilitating liquid-cooling of electronics racks of a data center, inaccordance with one or more aspects of the present invention;

FIG. 3 is a plan view of one embodiment of an electronic subsystem (ornode) layout illustrating an air and liquid cooling apparatus forcooling components of the electronic subsystem, in accordance with oneor more aspects of the present invention;

FIG. 4 depicts one detailed embodiment of a partially assembledelectronic subsystem layout, wherein the electronic subsystem includeseight heat-generating electronic components to be cooled, each having,in one embodiment, a respective cooling apparatus associated therewith,in accordance with one or more aspects of the present invention;

FIG. 5 is a cross-sectional elevational view of one embodiment of acooled electronic module comprising an electronic component to be cooledand a cooling apparatus, in accordance with one or more aspects of thepresent invention;

FIG. 6A depicts a top plan view of the deionization structure of thecooling apparatus depicted in FIG. 5, in accordance with one or moreaspects of the present invention;

FIG. 6B is a cross-sectional elevational view of the deionizationstructure of FIG. 6A, taken along line 6B-6B thereof, in accordance withone or more aspects of the present invention;

FIG. 7A is a cross-sectional elevational view of an alternate embodimentof a cooled electronic module, in accordance with one or more aspects ofthe present invention; and

FIG. 7B is a cross-sectional elevational view of the cooled electronicmodule of FIG. 7A, with the controllable diaphragm shown inflated topressurize the compartment of the cooling apparatus, in accordance withone or more aspects of the present invention.

DETAILED DESCRIPTION

As used herein, the terms “electronics rack” and “rack unit” are usedinterchangeably, and unless otherwise specified include any housing,frame, rack, compartment, blade server system, etc., having one or moreheat-generating components of a computer system or electronic system,and may be, for example, a stand-alone computer processor having high,mid or low end processing capability. In one embodiment, an electronicsrack may comprise multiple electronic subsystems or nodes, each havingone or more heat-generating components disposed therein requiringcooling. “Electronic subsystem” refers to any sub-housing, blade, book,drawer, node, compartment, etc., having one or more heat-generatingelectronic components disposed therein. Each electronic subsystem of anelectronics rack may be movable or fixed relative to the electronicsrack, with the rack-mounted electronics drawers and blades of a bladecenter system being two examples of subsystems of an electronics rack tobe cooled.

“Electronic component” refers to any heat-generating electronic deviceof, for example, a computer system or other electronics unit requiringcooling. By way of example, an electronic component may comprise one ormore integrated circuit die (or chips) and/or other electronic devicesto be cooled, including one or more processor chips, memory chips andmemory support chips. Further, the term “cold plate” refers to anythermally conductive structure having one or more channels orpassageways formed therein for flowing of coolant therethrough. Inaddition, “metallurgically bonded” refers generally herein to twocomponents being welded, brazed or soldered together by any means.

As used herein, a “liquid-to-liquid heat exchanger” may comprise, forexample, two or more coolant flow paths, formed of thermally conductivetubing (such as copper or other tubing) in thermal or mechanical contactwith each other. Size, configuration and construction of theliquid-to-liquid heat exchanger can vary without departing from thescope of the invention disclosed herein. Further, “data center” refersto a computer installation containing one or more electronics racks tobe cooled. As a specific example, a data center may include one or morerows of rack-mounted computing units, such as server units.

One example of facility coolant and system coolant is water. However,the cooling concepts disclosed herein are readily adapted to use withother types of coolant on the facility side and/or on the system side.For example, one or more of the coolants may comprise a brine, afluorocarbon liquid, a hydrofluoroether liquid, a liquid metal, or othersimilar coolant, or refrigerant, while still maintaining the advantagesand unique features of the present invention.

Reference is made below to the drawings, which are not drawn to scale tofacilitate understanding thereof, wherein the same reference numbersused throughout different figures designate the same or similarcomponents.

FIG. 1 depicts a raised floor layout of an air cooled data center 100typical in the prior art, wherein multiple electronics racks 110 aredisposed in one or more rows. A data center such as depicted in FIG. 1may house several hundred, or even several thousand microprocessors. Inthe arrangement illustrated, chilled air enters the computer room viaperforated floor tiles 160 from a supply air plenum 145 defined betweenthe raised floor 140 and a base or sub-floor 165 of the room. Cooled airis taken in through louvered covers at air inlet sides 120 of theelectronics racks and expelled through the back (i.e., air outlet sides130) of the electronics racks. Each electronics rack 110 may have one ormore air moving devices (e.g., fans or blowers) to provide forcedinlet-to-outlet airflow to cool the electronic devices within thesubsystem(s) of the rack. The supply air plenum 145 provides conditionedand cooled air to the air-inlet sides of the electronics racks viaperforated floor tiles 160 disposed in a “cold” aisle of the computerinstallation. The conditioned and cooled air is supplied to plenum 145by one or more air conditioning units 150, also disposed within the datacenter 100. Room air is taken into each air conditioning unit 150 nearan upper portion thereof. This room air may comprise in part exhaustedair from the “hot” aisles of the computer installation defined, forexample, by opposing air outlet sides 130 of the electronics racks 110.

Due to the ever-increasing airflow requirements through electronicsracks, and the limits of air distribution within the typical data centerinstallation, liquid-based cooling is being combined with theabove-described conventional air-cooling. FIGS. 2-4 illustrate oneembodiment of a data center implementation employing a liquid-basedcooling system with one or more cold plates coupled to highheat-generating electronic devices disposed within the electronicsracks.

FIG. 2 depicts one embodiment of a coolant distribution unit 200 for adata center. The coolant distribution unit is conventionally a largeunit which occupies what would be considered a full electronics frame.Within coolant distribution unit 200 is a power/control element 212, areservoir/expansion tank 213, a heat exchanger 214, a pump 215 (oftenaccompanied by a redundant second pump), facility water inlet 216 andoutlet 217 supply pipes, a supply manifold 218 supplying water or systemcoolant to the electronics racks 210 via couplings 220 and lines 222,and a return manifold 219 receiving water from the electronics racks210, via lines 223 and couplings 221. Each electronics rack includes (inone example) a power/control unit 230 for the electronics rack, multipleelectronic subsystems 240, a system coolant supply manifold 250, and asystem coolant return manifold 260. As shown, each electronics rack 210is disposed on raised floor 140 of the data center with lines 222providing system coolant to system coolant supply manifolds 250 andlines 223 facilitating return of system coolant from system coolantreturn manifolds 260 being disposed in the supply air plenum beneath theraised floor.

In the embodiment illustrated, the system coolant supply manifold 250provides system coolant to the cooling systems of the electronicsubsystems (more particularly, to liquid-cooled cold plates thereof) viaflexible hose connections 251, which are disposed between the supplymanifold and the respective electronic subsystems within the rack.Similarly, system coolant return manifold 260 is coupled to theelectronic subsystems via flexible hose connections 261. Quick connectcouplings may be employed at the interface between flexible hoses 251,261 and the individual electronic subsystems. By way of example, thesequick connect couplings may comprise various types of commerciallyavailable couplings, such as those available from Colder ProductsCompany, of St. Paul, Minn., USA, or Parker Hannifin, of Cleveland,Ohio, USA.

Although not shown, electronics rack 210 may also include anair-to-liquid heat exchanger disposed at an air outlet side thereof,which also receives system coolant from the system coolant supplymanifold 250 and returns system coolant to the system coolant returnmanifold 260.

FIG. 3 depicts one embodiment of an electronic subsystem 313 componentlayout wherein one or more air moving devices 311 provide forced airflow 315 to cool multiple components 312 within electronic subsystem313. Cool air is taken in through a front 331 and exhausted out a back333 of the subsystem. The multiple components to be cooled includemultiple processor modules to which liquid-cooled cold plates 320 (of aliquid-based cooling system) are coupled, as well as multiple arrays ofmemory modules 330 (e.g., dual in-line memory modules (DIMMs)) andmultiple rows of memory support modules 332 (e.g., DIMM control modules)to which air-cooled heat sinks are coupled. In the embodimentillustrated, memory modules 330 and the memory support modules 332 arepartially arrayed near front 331 of electronic subsystem 313, andpartially arrayed near back 333 of electronic subsystem 313. Also, inthe embodiment of FIG. 3, memory modules 330 and the memory supportmodules 332 are cooled by air flow 315 across the electronic subsystem.

The illustrated liquid-based cooling system further includes multiplecoolant-carrying tubes connected to and in fluid communication withliquid-cooled cold plates 320. The coolant-carrying tubes comprise setsof coolant-carrying tubes, with each set including (for example) acoolant supply tube 340, a bridge tube 341 and a coolant return tube342. In this example, each set of tubes provides liquid coolant to aseries-connected pair of cold plates 320 (coupled to a pair of processormodules). Coolant flows into a first cold plate of each pair via thecoolant supply tube 340 and from the first cold plate to a second coldplate of the pair via bridge tube or line 341, which may or may not bethermally conductive. From the second cold plate of the pair, coolant isreturned through the respective coolant return tube 342. Note that in analternate implementation, each liquid-cooled cold plate 320 could becoupled directly to a respective coolant supply tube 340 and coolantreturn tube 342, that is, without series connecting two or more of theliquid-cooled cold plates.

FIG. 4 depicts in greater detail an alternate electronic subsystemlayout comprising eight processor modules, each having a respectiveliquid-cooled cold plate of a liquid-based cooling system coupledthereto. The liquid-based cooling system is shown to further includeassociated coolant-carrying tubes for facilitating passage of liquidcoolant through the liquid-cooled cold plates and a header subassemblyto facilitate distribution of liquid coolant to and return of liquidcoolant from the liquid-cooled cold plates. By way of specific example,the liquid coolant passing through the liquid-based cooling subsystem iscooled and conditioned (e.g., filtered) water.

FIG. 4 is an isometric view of one embodiment of an electronic subsystemor drawer, and monolithic cooling system. The depicted planar serverassembly includes a multi-layer printed circuit board to which memoryDIMM sockets and various electronic devices to be cooled are attachedboth physically and electrically. In the cooling system depicted, asupply header is provided to distribute liquid coolant from a singleinlet to multiple parallel coolant flow paths and a return headercollects exhausted coolant from the multiple parallel coolant flow pathsinto a single outlet. Each parallel coolant flow path includes one ormore cold plates in series flow arrangement to facilitate cooling one ormore electronic devices to which the cold plates are mechanically andthermally coupled. The number of parallel paths and the number ofseries-connected liquid-cooled cold plates depends, for example, on thedesired device temperature, available coolant temperature and coolantflow rate, and the total heat load being dissipated from each electronicdevice.

More particularly, FIG. 4 depicts a partially assembled electronicsubsystem 413 and an assembled liquid-based cooling system 415 coupledto primary heat-generating components (e.g., including processor die) tobe cooled. In this embodiment, the electronic system is configured for(or as) a node of an electronics rack, and includes, by way of example,a support substrate or planar board 405, a plurality of memory modulesockets 410 (with the memory modules (e.g., dual in-line memory modules)not shown), multiple rows of memory support modules 432 (each havingcoupled thereto an air-cooled heat sink 434), and multiple processormodules (not shown) disposed below the liquid-cooled cold plates 420 ofthe liquid-based cooling system 415.

In addition to liquid-cooled cold plates 420, liquid-based coolingsystem 415 includes multiple coolant-carrying tubes, including coolantsupply tubes 440 and coolant return tubes 442 in fluid communicationwith respective liquid-cooled cold plates 420. The coolant-carryingtubes 440, 442 are also connected to a header (or manifold) subassembly450 which facilitates distribution of liquid coolant to the coolantsupply tubes and return of liquid coolant from the coolant return tubes442. In this embodiment, the air-cooled heat sinks 434 coupled to memorysupport modules 432 closer to front 431 of electronic subsystem 413 areshorter in height than the air-cooled heat sinks 434′ coupled to memorysupport modules 432 near back 433 of electronic subsystem 413. This sizedifference is to accommodate the coolant-carrying tubes 440, 442 since,in this embodiment, the header subassembly 450 is at the front 431 ofthe electronics drawer and the multiple liquid-cooled cold plates 420are in the middle of the drawer.

Liquid-based cooling system 415 comprises a pre-configured monolithicstructure which includes multiple (pre-assembled) liquid-cooled coldplates 420 configured and disposed in spaced relation to engagerespective heat-generating electronic devices. Each liquid-cooled coldplate 420 includes, in this embodiment, a liquid coolant inlet and aliquid coolant outlet, as well as an attachment subassembly (i.e., acold plate/load arm assembly). Each attachment subassembly is employedto couple its respective liquid-cooled cold plate 420 to the associatedelectronic device to form the cold plate and electronic deviceassemblies. Alignment openings (i.e., thru-holes) are provided on thesides of the cold plate to receive alignment pins or positioning dowelsduring the assembly process. Additionally, connectors (or guide pins)are included within attachment subassembly which facilitate use of theattachment assembly.

As shown in FIG. 4, header subassembly 450 includes two liquidmanifolds, i.e., a coolant supply header 452 and a coolant return header454, which in one embodiment, are coupled together via supportingbrackets. In the monolithic cooling structure of FIG. 4, the coolantsupply header 452 is metallurgically bonded in fluid communication toeach coolant supply tube 440, while the coolant return header 454 ismetallurgically bonded in fluid communication to each coolant returntube 452. A single coolant inlet 451 and a single coolant outlet 453extend from the header subassembly for coupling to the electronicsrack's coolant supply and return manifolds (not shown).

FIG. 4 also depicts one embodiment of the pre-configured,coolant-carrying tubes. In addition to coolant supply tubes 440 andcoolant return tubes 442, bridge tubes or lines 441 are provided forcoupling, for example, a liquid coolant outlet of one liquid-cooled coldplate to the liquid coolant inlet of another liquid-cooled cold plate toconnect in series fluid flow the cold plates, with the pair of coldplates receiving and returning liquid coolant via a respective set ofcoolant supply and return tubes. In one embodiment, the coolant supplytubes 440, bridge tubes 441 and coolant return tubes 442 are eachpre-configured, semi-rigid tubes formed of a thermally conductivematerial, such as copper or aluminum, and the tubes are respectivelybrazed, soldered or welded in a fluid-tight manner to the headersubassembly and/or the liquid-cooled cold plates. The tubes arepre-configured for a particular electronics system to facilitateinstallation of the monolithic structure in engaging relation with theelectronics system.

To facilitate heat transfer between the electronic components and theliquid-cooled structures, such as liquid-cooled cold plates describedabove, cooling apparatuses, cooled electronic modules and methods offabrication thereof are disclosed hereinbelow which employ boiling heattransfer. In the embodiments described herein, the working fluid for theboiling heat transfer comprises water, and specially-shaped deionizingstructures are provided which utilize, in one embodiment, deionizingmaterial (e.g., resin material), which ensures continued deionization ofthe water-based fluid, within which the electronic component to becooled is at least partially immersed. Employing immersion-cooling, incombination with a passive deionization structure, allows a superiorcoolant (i.e., a water-based coolant) to directly contact various partsof the electronic component, and thereby improve boiling heat transferbetween the electronic component and the liquid-cooled structure of, forexample, the above-described liquid-cooling system.

FIG. 5 depicts one embodiment of a cooled electronic module, generallydenoted 500, in accordance with one or more aspects of the presentinvention. Cooled electronic module 500 includes, in this embodiment, anelectronic component 511, such as an electronic chip or package, coupledto a printed circuit board 501 (through substrate 513, and solder bumps512, 514) with an associated back plate 502 (for example, a metal backplate). In this embodiment, an electrically non-conductive sealant 503is disposed between printed circuit board 501 and back plate 502. Acooling apparatus comprising a housing (or casing) 520 is mechanicallycoupled via securing mechanisms 505 to back plate 502.

As illustrated in FIG. 5, housing 520 is configured to at leastpartially surround and form a compartment 521 about electronic component511 to be cooled. In this embodiment, electronic component 511 isconnected to a chip carrier (or substrate) 513 via, for example, a firstplurality of solder ball connections 512. Substrate 513 is electricallyconnected to printed circuit board 501 via, for example, a secondplurality of solder ball connections 514 (and an underfill material). Anunderfill material 515 surrounds the first plurality of solder ballconnections 512, and seals the working fluid 522 within compartment 521from the first plurality of electrical connections and, in oneembodiment, the active surface of the electronic component 511 disposedin spaced, opposing relation to substrate 513.

The housing is a shell-like component that is attached to, for example,printed circuit board 501 using securing mechanisms 505, such as boltsor screws, and a sealing gasket 504, which is compressed between a lowersurface of the housing and an upper surface of the board, oralternatively, between a lower surface of the housing and an uppersurface of substrate 513, to which electronic component 511 directlycouples. Note that as used herein, the word “substrate” refers to anyunderlying supporting structure, such as substrate 513 or printedcircuit board 501 to which the electronic component is coupled, and towhich the housing may be sealed in order to form a fluid-tightcompartment 521 about the electronic component. Sealing gasket 504 sealsoff the compartment of the housing and assists in retaining the fluidwithin the sealed compartment.

As depicted, cooled electronic module 500 further includes aliquid-cooled cold plate 530 and a vapor-condensing region 540, disposedin an upper portion of the compartment 521. Liquid-cooled cold plate 530is bolted 535 to housing 520, and comprises, in this embodiment, aplurality of channels 532 through which a coolant (such as water)circulates, as described above in connection with FIGS. 3-4. Coolantpasses into the liquid-cooled cold plate through an inlet 531 andegresses through an outlet 533. Heat is conducted from thevapor-condenser structure 540 within compartment 521 across, in oneembodiment, thermal interface material 536 to liquid-cooled cold plate530 for rejection to the liquid coolant passing through the plurality ofcoolant-carrying channels of the liquid-cooled cold plate 530. In oneembodiment, the condenser fins 541 of the vapor-condenser structure areappropriately sized for the anticipated layer of vapor 523 to form inthe upper portion of the sealed compartment with operation of theheat-generating electronic component. Upon reaching the upper portion ofthe sealed compartment, the fluid vapor contacts the cool surfaces ofthe condenser fins. Upon making contact with the cool,vertically-oriented condenser fin surfaces, the fluid vapor undergoes aphase change process from vapor to liquid state, and the liquid dropletsfall back downwards due to gravity and the liquid's relatively higherdensity compared with the neighboring vapor region. By way of example,the vertically-oriented condenser fins might comprise pin fin or platefin structures. Further, the vertical length of the condenser fins mayvary to facilitate heat transfer from the fluid vapor to thevapor-condensing structure.

Housing 520 also comprises, in the illustrated embodiment, a fluid fillport 525, which may be employed to charge the cooled electronic modulewith, for example, water-based fluid. The module can be charged withfluid by first pulling a vacuum through the fluid fill port 525, andthen backfilling the compartment with the desired fluid charge. It iscontemplated that once filled with fluid, the cooled electronic modulewill function without further servicing of the fluid. In this regard,the amount of deionization material (discussed below) is appropriatelyselected to last for the lifetime of the electronic module.

FIGS. 5, 6A & 6B depict one embodiment of a deionization structure 550configured for and disposed within compartment 521 of the coolingapparatus. As illustrated, deionization structure 550 includes apedestal 554 for attaching the structure 550 to, for example, substrate513 or printed circuit board 501. In the embodiment, illustrated,deionizing structure 550 comprises a dome or frustum shape, and includesa capping plate 552 with a plurality of vapor release openings 553. Adeionization, cartridge-type shell 555 forms the sidewalls of thedeionization structure and includes fluid openings 600 on both the innerwall and the outer wall to allow fluid to pass through the shell. Theshell comprises, in one embodiment, a polymer casing which contains thedeionization material. In one embodiment, the deionization materialcomprises cation and anion spherical resin particles. The fluid openingsare sized sufficiently small to ensure that these particles remaincontained within the shell. As shown in FIG. 5, the deionizationstructure at least partially surrounds and forms a secondary, boilingcompartment 551 about electronic component 511 to be cooled.

In one embodiment, the fluid charge in the compartment is deionizedwater, and the deionization structure is a passive deionization capwhich covers the electronic component to be cooled, and forms asecondary, boiling chamber about the electronic component to be cooledwithin which the fluid boils, for example, from one or more surfaces ofthe electronic component. The deionization structure is, in oneembodiment, a dome-like structure, with the top portion comprising aflat, capping plate that does not contain deionization properties, buthas openings to allow vapor to escape upwards from the periphery of theelectronic component. As noted, the deionization structure is designedto last for the anticipated lifetime of product operation, for example,five years or more. The walls of the deionization structure may besloped, and the shape of the structure dome-shaped to force vapor to bereleased upwards towards the top of the structure, in a smaller, centralregion of the structure, which limits the chances of condensing waterre-entering the boiling chamber 551 via the top vapor release openings(and thus bypassing the deionization material). The sloped walls anddome-shaped or frustum-shaped structure further facilitates exposing alarger portion of the deionization material (for example, deionizerpellets) to the water condensate, thereby increasing the amount of fluid556 forced to flow through the deionization cartridge-type shell 555.

In one example, the deionization material comprises a commercial resinmaterial, such as ResinTech MBD-10-SC, which is a mixture of hydroxidefrom Type One strong base gel anion exchange resin and hydrogen fromstrong acid sulfonated gelular polystyrene cation exchange resin,offered by ResinTech, Inc., of West Berlin, N.J., U.S.A. Physicalproperties of this material include:

Functional Structure Cation (Hydrogen form) RSO₃ ⁻H⁺ (Gel) Anion(Hydroxyl form) R₄N⁺OH⁻ (Type One Gel) Physical Form Tough, SphericalBeads Screen Size Distribution +16 mesh (U.S. Std.) <2 percent −45 mesh(U.S. Std.) <2 percent Volume Ratio (as shipped): Cation 40 percentAnion 60 percent Total Capacity Cation 1.95 meq/mL min. (Na⁺ form) Anion1.40 meq/mL min. (Cl⁻ form) Column Operating Capacity Initial cycleElectrolyte Breakthrough 0.60 meq/mL (13 Kgrs/cu. ft.) min. MoistureContent (as shipped) 60 percent max. Maximum Operating TemperatureNon-regenerable 80° C. (175° F.) Regenerable 60° C. (140° F.) OperatingFlow Rate 2 to 10 gpm/cu. ft. (typical) pH Range 0-14 Metals Content(typical ppm dry wt) Iron (Fe) <100 Copper (Cu)  <50 Lead (Pb)  <50

In operation, as the fluid (e.g., water) absorbs heat, the fluid in thesecondary, boiling compartment 551 undergoes phase change from liquidphase to vapor phase, and thus utilizes its latent heat of vaporizationfor cooling purposes. The vapor 523 generated travels upwards throughthe vapor release openings 553 in the capping plate 552 of thedeionization structure 550, since the vapor possesses a much lowerdensity compared with the surrounding liquid. Upon reaching the upperportion of compartment 521, the fluid vapor comes in contact with thecooled surfaces of the vapor condenser 540, such as the surfaces of thecondenser fins 541. These condenser fins are cooled by means of thermalconduction coupling to, for example, liquid-cooled cold plate 530. Onmaking contact with these cool, vertical surfaces, the water vaporundergoes a second phase change process from vapor to liquid state, andthe liquid droplets fall back downwards due to gravity and theirrelatively higher density compared with the neighboring vapor region.Liquid fluid 522 in the bottom portion of the compartment 521 is drawnfrom the high-pressure side of the deionization structure 550 to thelower-pressure side, to replace the vapor that exits the boilingcompartment 551. As long as the boiling and condensation coolingprocesses are in equilibrium, and are commensurate with the heatgenerated by the electronic component, the cooling apparatus willsuccessfully transport heat from the electronic component to theliquid-cooled cold plate. Note that in the configuration illustrated,the top inside portion of the vapor condenser may comprise a thin layermade up of non-condensable gases, such as air, which may leave theliquid and travel upwards. Also note that, while illustrated with aliquid-cooled cold plate, an air-cooled heat sink could alternatively beemployed in combination with the housing 520 of the cooling apparatus.

As described above, fluid port 525 extends through housing 520. Thisfluid port is a sealable structure used to fill compartment 521 with adesired amount of water-based fluid 522. This can be accomplished bydrawing a vacuum to result in a sub-atmospheric pressure inside thecompartment in a normal operating environment. It is desirable to createsub-atmospheric pressure within the compartment because water boils at100° C. under atmospheric conditions, and to cause the water to boil ata much lower temperature, a partial vacuum is utilized. To coolelectronic components that have a maximum allowable temperature, whichcould be in the 60°-100° C. range, it is necessary to have water thatboils in the 30°-60° C. range, thus requiring a vacuum. While it isdesirable for the water to boil at a temperature less than the 100° C.,it is still practical to design the cooling apparatus to contain waterthat boils at a temperature that is sufficiently above ambient roomtemperature.

FIGS. 7A & 7B depict an alternate embodiment of a cooled electronicmodule 500′, in accordance with an aspect of the present invention. Thisalternate embodiment of the cooled electronic module is substantiallyidentical to that described above in connection with FIGS. 5-6B. Theexception is the provision of an inflatable diaphragm 700 extendingthrough housing 520 into compartment 521. The inflatable diaphragm,which is shown depressurized in FIG. 7A, and pressurized in FIG. 7B, isa pressure regulation structure that can be inflated to varying degreesof inflation to correspondingly reduce the open volume insidecompartment 521 by varying degrees, thus allowing the pressure insidethe compartment to be adjusted. By changing the pressure inside thecompartment, the working fluid can be made to boil at differenttemperatures, thus allowing for control of the electronic componenttemperature, or control of the cooling capability of the coolingapparatus.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the invention. Asused herein, the singular forms “a”, “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprise” (andany form of comprise, such as “comprises” and “comprising”), “have” (andany form of have, such as “has” and “having”), “include” (and any formof include, such as “includes” and “including”), and “contain” (and anyform contain, such as “contains” and “containing”) are open-endedlinking verbs. As a result, a method or device that “comprises”, “has”,“includes” or “contains” one or more steps or elements possesses thoseone or more steps or elements, but is not limited to possessing onlythose one or more steps or elements. Likewise, a step of a method or anelement of a device that “comprises”, “has”, “includes” or “contains”one or more features possesses those one or more features, but is notlimited to possessing only those one or more features. Furthermore, adevice or structure that is configured in a certain way is configured inat least that way, but may also be configured in ways that are notlisted.

The corresponding structures, materials, acts, and equivalents of allmeans or step plus function elements in the claims below, if any, areintended to include any structure, material, or act for performing thefunction in combination with other claimed elements as specificallyclaimed. The description of the present invention has been presented forpurposes of illustration and description, but is not intended to beexhaustive or limited to the invention in the form disclosed. Manymodifications and variations will be apparent to those of ordinary skillin the art without departing from the scope and spirit of the invention.

What is claimed is:
 1. A method of fabricating a cooled electronicmodule comprising: securing a housing about an electronic component tobe cooled, the housing at least partially surrounding and forming acompartment about the electronic component to be cooled; disposing afluid within the compartment, wherein the electronic component to becooled is at least partially immersed within the fluid, and wherein thefluid comprises water; and providing a deionizing structure within thecompartment, the deionizing structure comprising deionizing material,the deionizing material ensuring deionization of the fluid within thecompartment, wherein the deionizing structure is configured toaccommodate boiling of the fluid within the compartment.
 2. The methodof claim 1, wherein the deionization structure disposed within thecompartment at least partially surrounds and forms a secondary, boilingcompartment about the electronic component to be cooled, thedeionization structure comprising vapor release openings in an upperportion thereof.
 3. The method of claim 2, wherein the deionizationstructure comprises a deionization shell with openings to allow fluid topass therethrough, the deionization shell comprising a cartridge-typeshell containing the deionization material.
 4. The method of claim 3,wherein the deionization material comprises cation and anion sphericalresin particles, and the fluid openings in the deionization shell aresmaller than the cation and anion spherical resin particles containedwithin the deionization shell.
 5. The method of claim 4, wherein thedeionization shell is frustum-shaped, and includes a capping platecomprising the vapor release openings.
 6. The method of claim 1, whereinthe deionization material is in contact with the fluid within thecompartment, and passively deionizes the fluid within the compartment.7. The method of claim 1, further comprising providing a vapor-condenserdisposed in an upper portion of the compartment, and facilitatingcooling of fluid vapor rising to the upper portion of the compartment,and wherein the method further comprises providing one of aliquid-cooled cold plate or an air-cooled heat sink coupled to thehousing and cooling the vapor-condenser disposed in the upper portion ofthe compartment.
 8. The method of claim 1, wherein the compartment is asealed compartment, and wherein the method further comprises providingan inflatable diaphragm at least partially disposed within thecompartment, the inflatable diaphragm being controllable to controlpressure within the sealed compartment.